Today, power converters are commonly used in conjunction with various devices such as mobile phones, tablets, computers, and other adaptive and non-adaptive devices (hereafter, each an “adaptive device”) to convert line voltages, such as the U.S. standard 120 volts AC, into various output voltages and currents (hereafter, each a “load request”) then desired by an adaptive device. For example, load requests may include a request for a power converter to provide 5 volts at 1 Amp, while at a later time request 9 volts at 3 Amps, or other power levels, and vice versa. The reasons for such varying load requests are beyond the scope of the present disclosure, but, such requests may be presented to power converters at any time and commonly within wide variances of voltages and currents.
To address such varying load requests, three methods for controlling the operation and voltages and currents (collectively, the “output power”) output by a power converter, such as a switch mode power converter, a buck converter, and other configurations (hereafter, each a “power converter”), to an adaptive device are commonly known. These methods include Primary Side Regulation (“PSR”), Secondary Side Regulation (“SSR”), and a combination of PSR and SSR (“combined regulation” or “CR”), where output voltages are often controlled using SSR and output currents are often controlled using PSR.
With SSR, the output power converter can be controlled with high sophistication such that, for example, variations in such output voltages and currents deviate from a desired level by less than ±5 percent and ±10 percent, respectively. This level of control, however, comes with certain known monetary costs, losses of power efficiency, heat concerns, and otherwise. For example, one commonly known SSR approach may include use of a sensing resistor, for sensing output current, and two or more opto-couplers for controlling both the output voltage and output current by controlling the primary side switching of a switch mode power converter. The sensing resistor consumes power, and the opto-couplers add costs and complexity.
For PSR, similar concerns arise. While PSR eliminates the need for a sensing resistor, it does so at the cost of providing less certainty in output voltage and current control. It is commonly appreciated that PSR is typically unable, at reasonable costs, to provide the “highly sophisticated” control achievable with SSR. Further, when PSR is used without opto-couplers, output voltages and currents are controlled based on estimates—such estimates commonly being determined based on the voltages and currents generated by tertiary windings on transformers used in power converters or using other known techniques. Such estimates typically induce an error between the actual voltages and currents output by a power converter versus the requested output voltages and currents.
For combined regulation, CR, similar concerns arise. While a sensing resistor is not required to control output current, added complexity and costs are commonly incurred by using an additional opto-coupler to communicate output current load requests to components used on the primary side of the power converter. Thus, improvements on how to communicate load requests in power converters are needed that eliminate costs, reduce energy consumption, and address the above and other known concerns.
The various embodiments of the present disclosure address the above and other concerns by providing highly sophisticated control of output voltages and currents by power converters to adaptive devices based on then existing load requests by using a single opto-coupler and supporting circuitry and components configured to communicate communication signals provided by an adaptive device, such signals indicating a then desired output current and voltage desired by the adaptive device, to the primary side of a power converter. The primary side of the power converter being adapted to control the output current of the power converter, while the second side controls the output voltage. Accordingly, as discussed below, the various embodiments described avoid costs, inefficiencies and complexities arising from the use of sensing resistors and multiple opto-couplers of prior art approaches.